GRASP's "PhillieBot" Throws Out First Pitch at Phillies Game

Meet PhillieBot, a one-armed, three-wheeled contraption that threw out the ceremonial first pitch before the April 22 Phillies game against the Milwaukee Brewers. It is a robot built by Penn Engineering's General Robotics, Automation, Sensing and Perception (GRASP) Laboratory as the headline attraction for Science Day at the Ballpark.

The pitching robot is the creation of Vijay Kumar, UPS Foundation Professor and deputy dean of education in the School of Engineering and Applied Science, and his collaborators in the Department of Mechanical Engineering and Applied Mechanics: staff members Jamie Gewirtz and Jordan Brindza, as well as graduate student Christian Moore.

Comprised of systems that GRASP members are using in their ongoing research, the robot has an arm that is made by Barrett Technology and is designed to replicate smooth, fluid motion. When the robot is not throwing fastballs, the GRASP lab researchers are teaching it to operate in common human situations that require a certain amount of dexterity and control, such as locating and opening a door handle.

Not your Average Pitching Machine

You might think PhillieBot does the same thing as those machines that spit out baseballs at batting cages. "Pitching machines," of course, have been used for years to emulate a real pitcher and allow batters to take batting practice. But the standard pitching machine generally uses a pair of revolving rubber wheels, propelling a baseball between them to emulate a pitch. In contrast, the PhillieBot's computer brain can be infinitely tweaked to change pitch velocity and trajectory, and its arm is a sleek, programmable instrument that also can be used in surgical and manufacturing applications. Moreover, PhillieBot can move.

The engineers started with a Segway, a motorized, two-wheeled vehicle, and replaced the handlebar section with the robotic arm. They then added a third wheel for stability. On top of the arm, the engineers attached a "hand," a store-bought plastic scoop used to play jai-alai. But by game time, the plan is to have replaced the plastic hand with a lighter, stronger carbon-fiber model made by Christian Moore, a doctoral student in Mechanical Engineering. Just underneath the hand, the group attached a pneumatic cylinder, which delivers a burst of compressed carbon dioxide at just the right instant to snap the wrist forward and release the ball. By game time, the robot will also have a small black head with one swiveling lens for an eye.

From Idea to Implementation

The idea to build a robot pitcher came from Gerri Trooskin, director of the Philadelphia City Science Festival. She pitched her proposal to the GRASP Laboratory, who were glad to oblige. Rebecca Stein, GRASP's Associate Director of Research and Educational Outreach, worked to coordinate the details for the pitch to take place.

After a month and a half of assembling parts and writing software in their spare time, Penn Engineers Jordan Brindza and Jamie Gewirtz traveled out to the mound at Citizens Bank Park for a final test with PhillieBot.

At the touch of a button, the robot's jointed arm reared back and then moved steadily toward home plate. At the top of its delivery the robot shot the ball homeward with a flick of its mechanical wrist. The ball appeared to be traveling no more than 30 or 40 miles an hour, but that was by design, as the Phillies organization, to ensure safety, did not want anything approaching the speeds of their own Roy Halladay and his rotation mates.

To see PhillieBot in action and to learn more about its development, watch the video!